Lattice frame beam and column of the chord, CHS and compose the individual component calculation length ` L_O ` should be used according to the following provisions:
1. Within the rigid frame plane, the distance between nodes is taken for each bar member.
2. Outside the rigid frame plane, the distance between the abdominal rod and the affix rod is taken as the distance between the nodes, and the distance between the string rod and the lateral support point is taken as the distance. If there is any change in the internal force of the compressed chord within the length range, it shall be calculated according to the regulations:
